焊缝金属厚度方向的流动与洋葱瓣花纹的形成  

The flowing behavior of weld metal in thickness of the plate and the formation mechanism of the onion ring

作　　者：柯黎明[1] 潘际銮[1] 邢丽[2] 黄永德[2] 

机构地区：[1]清华大学先进成形制造教育部重点实验室,北京100084 [2]南昌航空大学材料科学与工程学院,南昌330063

出　　处：《焊接学报》2008年第7期39-42,共4页Transactions of The China Welding Institution

基　　金：江西省自然科学基金资助项目(0450090)

摘　　要：研究了在铝合金薄板与铜箔交替叠加的多层板搅拌摩擦焊过程中焊缝金属的塑性流动行为。结果表明,用带螺纹的搅拌针焊接时,搅拌针周围金属沿螺纹在焊缝厚度方向产生剧烈的流动,在螺纹端部脱离搅拌针并向周围挤压母材,形成实心环形挤压区,与周围母材有明显的界面。洋葱瓣花纹是实心环形挤压区在焊缝横截面上的表现形式。搅拌针表面的螺纹提供金属在焊缝厚度方向流动的驱动力。搅拌头顺时针旋转时,用左螺纹搅拌针焊接的焊缝横截面上,洋葱瓣花纹的中心偏向焊缝底部;用右螺纹搅拌针焊接的横截面上,花纹的中心偏向焊缝表面。The plastic flow behavior of the weld metal during friction stir welding was analyzed by using the multi-plate piled up with several thin copper foils and aluminum sheets and the copper foils serves as a marker material.The results show that there is a serious material translation in the thickness of the weld along the screw thread if using a pin with screw threaded surface.These flowing materials will slough off from the thread at the tip or root of the pin and squeeze into the surrounding area,forming a solid ring with the center being the circle of tip or root of the pin.There is a distinct boundary between the solid ring and its surrounding parent metal.The onion ring is actually the projecting picture of the solid ring cut at the cross section of the weld.The driving force of the metal flow in the thickness of the weld is the pressure of the skew threads on the pin surface to its surrounding plastic metal.When the stir tool rotates clockwisely,the center of the onion rings deflect to the bottom of the weld in the case of the pin with left-hand skew thread on its surface,or deflect to the up surface of the weld in the case of the pin with right-hand skew thread on its surface.

关 键 词：搅拌摩擦焊 塑性流动 洋葱瓣花纹 

分 类 号：TG453.9[金属学及工艺—焊接]